Abstract:
The greater cane rat, Thryonomys swinderianus, utilizes high fibrous plant material and is an
important meat source in West Africa. An insight in its digestive physiology will enhance our
understanding of its feeding habits. Digestibility coefficients of the food were determined
during two seasons before the animals were euthanased. The distribution and concentrations
of nutrients and energy in different parts of the gastrointestinal tract were determined at the
time of day when animals practised coprophagy. Trial 1 diet in the wet season consisted of 36%
neutral detergent fibre (NDF), 11% protein and 49% dry matter, while the Trial 2 diet in the dry
season consisted of 53% NDF, 8–9% protein and 89% dry matter. The Trial 2 animals on the
poor diet increased their daily nutrient intake, possibly increased the volume of digesta and
practised frequently cophrophagy, so that faecal production was reduced and digestibility
coefficients were relatively high. Coprophagy increased both protein and energy intake as soft
pellets in the distal colon had higher protein and energy content than the hard faeces. Energy,
protein and acid-detergent fibre were retained in the caecum of Trial 1 females and the caecum
and proximal colon of the Trial 2 animals 16 hours after feeding, illustrating the importance of
these two regions in the fermentation process. Water was absorbed in the distal colon as dry
matter content of digesta increased 53%, 4% and 56% from the proximal colon to the distal
colon. Animals produced hard faeces with only 16% and 5% lower moisture content in the dry
season, compared to that produced in the wet season, as water was not a limiting factor during
the trials. It was concluded that an increase in daily food intake, an increase in coprophagy and
the presence of a colonic separation mechanism (that retains small particles) enable the
greater cane rat to utilize high fibrous plant material. These digestive strategies seem to be
comparable to those observed in other hystricomorph rodents.
